Chronic disorders of the respiratory system are significant causes of morbidity and mortality whose incidence is increasing worldwide. According to World Health Organization estimates, about 80 million people have moderate to severe chronic obstructive lung disease (COPD), and more than 3 million people died of COPD in 2005 (˜5% of all deaths globally). COPD was the fifth leading cause of death in 2002, and estimates suggest that it will be the third leading cause of death worldwide in 2030 unless major risk factors, particularly tobacco use, can be successfully curbed. Asthma is also a significant global health problem, affecting an estimated 300 million individuals worldwide. Both asthma and COPD can have debilitating effects on patients' daily functioning and quality of life, particularly when severe. These diseases also represent significant burdens in terms of health care costs and lost productivity.
Pharmacological therapies such as bronchodilators and corticosteroids are widely used in the treatment of asthma and COPD. However, a significant proportion of patients experience persistent symptoms despite such interventions. Furthermore, these agents can be associated with significant side effects. There is a need for additional pharmacological therapies for treating disorders affecting the respiratory system.